Power falloff at operating temperature

[DBuchheit]

I've noticed that my truck runs really strong while warming up, but the power falls off when it reaches operating temperature. This seems odd to me. I've checked my AIT sensor (even replaced it). Anyone else have this problem or can you suggest a solution? Yes, I know not to push the engine hard when cold.



Thanks

 

[MidwestMotorman]

suggestions

Weak lift pump or dirty air cleaner?

Perhaps a boost leak on a warm hose? Check and retighten clamps.

Maybe an intake manifold leak or loose air horn?

 

[chuck3]

May have a bad lift pump, have you checked your pressures?

 

[mopars1]

The controller puts more timing in when the engine is cold. I don't really know if this is what you are experiencing, but I do notice a difference in the low end performance of my truck when the engine temps are low.

 

[MidwestMotorman]

Forgot to mention another big killer of power, the catalytic converter. If yours has been chopped out, then back to the other suggestions.

 

[Diesel Freak]

look at his sig... he has no cat.



Basicly it has to do with the temperature of the engine, and the intake air temp. The ECM tweaks timing a bit as the engine warms up... nothing to be worried about.

 

[MidwestMotorman]

wrong sig???

Diesel Freak- I think you are looking at the sig of the wrong person... RamBoat does not mention losing the kitty in his sig.



I see no loss in power in my 99 from cold to warm. I actually have to be careful not to push it too hard when it is cold.



That reminds me, RamBoat, do you notice this power loss only when the "wait to start" light comes on (starts below 60* deg air temp I think), or on all cold starts?

 

[Diesel Freak]

2001. 5's dont have cat's



My truck has always done that... very apparent when the temp drops from 80 during the day to 40 at night.

 

[Gary - K7GLD]

Just crawled under my new '02 this afternoon, and see what APPEARS to be an anti-resonance chamber just ahead of the muffler - but no cat that *I* can see - at least I don't THINK that thing ahead of the muffler is a cat - not very hot as cats usually are after the vehicle has been driven for a while...



AND, mine seems to get STRONGER after warming up...

 

[Steve Campbell]

Marco posted about a water temp sensor...

about six months ago. Seems to me... he was saying that your problem was/is due to a faulty one of these. You might do a search, or he might chime in here, or PM him for more info. Good luck.

 

[MidwestMotorman]

Thanks for the education Diesel Freak. D-C must have saved a ton of $$$ doing that.

 

[DBuchheit]

I have both boost and fuel pressure gauges, no problem there. I've replaced both the air filter and fuel filters, so that shouldn't be a problem.



I think the water temp sensor might have some merit. My dash temp gauge always reads higher than my SPA temp gauge.



Any other suggestions?

 

[Gary - K7GLD]

Ramboat - yeah, *I* have another question - what is the MAX turbo boost you see with your truck? I will be using mine to tow a 5th wheel in the hills, and am curious as the what these later trucks generate in boost right from the factory under full load...



Thanks

 

[DBuchheit]

Originally posted by Gary - KJ6Q

Ramboat - yeah, *I* have another question - what is the MAX turbo boost you see with your truck? I will be using mine to tow a 5th wheel in the hills, and am curious as the what these later trucks generate in boost right from the factory under full load...



Thanks

My gauge reads 20 PSI